"I made a serious mistake," he said through tears. "I never wanted this to happen. It happened and I can't take it back, but if I could, I would. I would definitely take everything I did back. I just hope the family can forgive me."

Sheeley's sentence was stipulated as part of his plea agreement, with the approval of the victim's family.

He dodged a first-degree murder charge by pleading guilty after a second suspect, Jesus Reyna, allegedly told police the two lured Crall into a car and drove him to the mountains where they shot him to death.

Prosecutors and the victim's family dedicated their comments during Monday's hearing to Crall, remembering his life and questioning his death.

Family members said Crall was an intelligent, compassionate person who always went out of his way to help others. Prosecutors noted that he'd overcome multiple challenges in his life, becoming a skilled auto mechanic even after dropping out of school and learning to walk again after a battle with brain cancer.

"Despite all his problems, he really tried to help people," deputy district attorney Christine Word said. "He tried to lead a good life."

Sheeley's personal history also came up in court. Prosecutors, the defense attorney and Sheeley himself referenced his traumatic childhood - although they were vague on details - and his use of methamphetamines.

"Many people who are addicted to that substance don't go on to kill people, but it's how Mr. Sheeley became the man he is today and likewise what led to his being with Conrad that day," defense attorney Trevor McFee told the judge, adding that the events, "show the extent to which methamphetamines and that type of lifestyle leads to horrific consequences."

Reyna, also of the Denver area, pleaded guilty to avoid a first-degree murder charge, and was set to be sentenced Monday afternoon, but fired his attorney at the hearing and instead asked to withdraw his plea and take his chances with a jury.

Residents discovered the body of 31-year-old Crall, an occasional mechanic and resident of Kiowa, on Oct. 9, 2010, as they were hiking around their property, according to press reports at the time.

He was lying face down just yards from I-70, shot three times by two different firearms. The fatal shot hit him in the head and the death was ruled a homicide, an arrest affidavit for Reyna states.

Investigators soon discovered the last time Crall had been seen alive was in late September, nearly three weeks prior. He'd been working on the car of an acquaintance and had left to meet someone with whom he seemed to be angry, saying the person was going to return some of his belongings.

Detectives pulled Crall's cellphone records and found he'd been in touch with a number belonging to Sheeley the day he was last seen. That was also the day all outgoing activity on his phone stopped.

But it was unclear whether Sheeley had actually been in possession of his phone the day investigators were beginning to suspect Crall had been murdered, and the case eventually ran cold.

Two years later, in March 2012, investigators got back in touch with the phone company and discovered something more interesting than phone records. Using cellphone towers to track the locations of the two devices, authorities realized Crall and Sheeley's phones had apparently come closer and closer together the day he was apparently killed and then moved together up the Interstate 70 corridor toward Georgetown and then back down again, according to the affidavit.

Investigators met with Sheeley, who was in jail on an unrelated charge, and he spun a story that starred Thomas Claeys - a man who had dated Crall's mother and was, according to several accounts, a methamphetamine user and gun owner who openly hated Crall - as the killer, the affidavit states.

Sheeley said Claeys had threatened him into accompanying him up to the mountains, where he shot and killed Crall himself with two different weapons.

But another witness told a different story, saying Sheeley had bragged about killing Crall himself with the help of another man nicknamed "Sleepy."

Sleepy turned out to be Reyna, who later admitted to driving Sheeley to meet Crall at a Denver gas station and then transporting the three of them up I-70 to the Clear Creek location where Crall was shot, according to the affidavit.

Neither man's motive for the murder is clear in the affidavit. Reyna reportedly told authorities Sheeley wanted to kill Crall because he'd stolen a woman's purse, which contained valuable items. Reyna said he'd agreed to drive him to the mountains for gas money.